In September, 25 individuals or organizations wrote checks of $1 million or more to super PACs, according to Sunlight's analysis of the last full month of campaign expenditure reports that we will see before the election, filed overnight with the Federal Election Commission. While Republicans had the cash advantage, Democrats showed they are well in the game when it comes to recruiting sugar daddies.

Big-check writers, led by labor unions and media moguls, pumped a total of $26.5 million into Democratic coffers.

That compared to $31 million for Republicans, one-third of which was provided by a single individual: Joe Ricketts, owner of the Chicago Cubs and the founder of TD Ameritrade. As Sunlight earlier reported, he gave $11.5 million to Ending Spending Action Fund, which so far has spent most of its money on ousting President Barack Obama.

Most of September's big donors to GOP super PACs are familiar names, including retired pharmaceutical exec Richard Roberts and Texas tycoon Harold Simmons. But there is one intriguing newcomer: The Armstrong Companies, a western Pennsylvania conglomerate whose business interests run the gamut from real estate to telecom, gave a donation of $1.3 million “in-kind cable access” to American Crossroads, a super PAC founded by former Republican National Committee Chairman Ed Gillespie and former President George W. Bush's political guru, Karl Rove.

Notably absent from the September million-dollar check club: Sheldon Adelson, the gambling titan who has pumped $18 million into the campaign so far this year. His wife, Miriam, has been good for another $17.6 million. It's possible the Adelsons have donation fatigue, but it's also possible that he and other big donors have shifted their giving to the political non-profits who, thanks to their 501(c) status, never have to identify contributors. So far, those groups have spent almost $186 million trying to influence this year's election.

A chart of September's million dollar donors is below. For an idea of what they might get for their money, check out Sunlight's Stealthy Wealthy series.